Miniature bulb and socket construction



Aug 5, 1940- M. KLEIN Er A1. 2.210.764

MINIATURE BULB AND SOCKET CONSTRUCTION Aug. 6, 1940. M. KLEIN ET Al.

MINIATURE BULB AND SOCKET CONSTRUCTION Filed Nov. 29. 1938 2Sheets-Sheet 2 latented Aug. 6, i940 PATENT OFFICE MINIATURE BULB ANDSOCKET CONSTRUCTION Maximilian Klein, Sellersville, and William E.

Pfelexg- South Perkasie, Pa.,

assignors to United States Gauge Company, Sellersville, Pa., acorporation of Pennsylvania Application November 29, 1938, Serial No.243,047

Claims. (Cl. 176-32) The present invention relates to a vnovel electrici bulb and socket structure. More particularly, the present inventionrelates to a novel miniature lamp bulb and socket structure adapted foruse 5 in the illumination of dial and pointer instruments, inscribed'or' decorative panels, small electrical inspection and medicalinstruments, and devices of like characteristics.

' Electrical bulbs of the above mentioned characl0 ter are extremelysmall having anoverall length of approximately one-half an inch and adiameter of approximately one-eighth of an inch. As a result of thesmall size of these bulbs, diiculty has been experienced in assemblingthe glass bulb with its extremely fine filaments in the bulb base. l. Itis, therefore, the primary object of the present invention to provide anexceedingly simple base structure that will enable ready assembly andconnection of the glass bulb and filament,

and convenient connection of the'lamp to the instrument casing by meansof a cap with which the lamp is removably associated.

A further important object of the present inv vention resides in theprovision of an electric lamp and base assembly capable of beinginserted into a socket portion so as to make contact with the socketforwardly of the base of the lamp or adjacent the end of the bulb that'contains the filament. 4

A further object of the present invention resides in the provision of anelectrical lamp made up of four relatively simple parts designed to beheld in assembled relation'with each other and with the glass bulb by asuitable cement.

' Still another object of the present invention resides in the provisionof a novel socket adapted to receive a miniature light bulb.

A further object of the present invention resides in the construction ofa lamp socket having a permanent contact for one terminal of the bulband a readily removable contact designed to complete the circuit to theother terminal of the bulb and to secure the bulb in snug engagementwith the socket.

Further objects of the invention will appear from' the followingdescription when read in conjunction with the appended claims andattached` drawings, wherein:

Figure 1 is a transverse sectional view through a bulb socket made inaccordance with the present invention and a preferred form of bulb inassembled relation therein illustrating one method of employing thepresent bulb and socket structures;

Figure 2 is a transverse sectional view of the bulb assembly of Figure 1illustrating the manner oil insulating the contact elements from eachother and of securing the glass bulb in place;

Figure 3 is a plan View of the bulb of Figure as viewed from the frontof the bulb;

Figure 4 is a plan view of the bulb of Figure 2 5 viewed from the rearof the bulb;

Figure 5 is a plan view of a dial and pointer instrument illustrating anapplication of the method of illumination disclosed in Figure 1;

Figure 6 isa view similar to Figure 1, illustrat- 10 ing a modified formof bulb made in accordance with the present invention.

Figures 7 to 9 are views corresponding to Figures 2 to 4 illustratingthe modied form of bulb shown in Figure 6; and

Figure 10 is a View similar to Figure 1, illustrating a furthermodification of the bulb structure used in another manner to illuminatean instrument such as that shown in Figure 5.

With continued reference to the drawings wherein like reference numeralsare used to indicate the same parts throughout the several figures,numeral I0 indicates generally a lamp made in accordance withthe presentinvention, and 25 numeral II indicates generally the novel socket of thepresent invention.

Lamp I0 comprises a glass bulb `I2 having the usual filament I3 thereinandprotruding lament connections I4 and' I5 extending from the rear ofthe glass bulb. Glass bulb I2 is preferably manufactured in accordancewith well known practices and is assembled with the novel bulb baseassembly I6 of the present invention in the following manner.

Base assembly I6 comprises a metal contact Il composed of a relativelynarrow strip of metal having a flange I8 at one end thereof. Contact Ilcomprises one contact element for lamp I0 and is connected to filamentlead I4 by a suitable solderingoperation at I9. 40

After contact I'I is connected to filament lead I4 it is forced into aninsulating sleeve 2l and the shoulder I8 is brought into abuttingrelation with end 22 of sleeve 2|.

The assembled glass bulb I2, contact Il and 45 sleeve 2 I is thenprovided with a further contact 23 having a flange 24 at one endthereof. Contact 23 is identical in structure to contact Il and isforced into the opposite end of sleeve 2| at a point substantiallydiametrically opposite contact Il until flange 24 abutsI end 25 ofsleeve 2I. Filament lead I5 is then soldered to sleeve 23 at 26. Thespace surrounding glass bulb I2 and the rear of sleeve 2| is then lledwith an insulating 5 level.

and: 38.

cement 21 by pouring the cement in its plastic condition into the openrear end of sleeve 2|. Cement 21 completely nils the space between glassbulb I2 and sleeve 2| so as to unite these ele ments and contact stripsI1 and. 23 together. From the above description it will be clear thatbulb III is made of relatively few and. simple parts, and that, due tothe fact' that the various parts are readily accessible during theassembly operation, very little dilculty is experienced.l in making thesoldered connections |9 and 28, and in assembling the glass bulb I2 withits be I8.

While lamp I8 may be used in any Suitable socket structure, the socketstructure." of the present invention is preferred. Socket comprises abody portion 3| of insulating material having a bore' 32 therein. 'I'heupper end of bore 32 is preferably'enlarged as at 33 to provide anannular shoulder 34. At suitable points in the interior of bqdy`3|thewalls of bore 32 are provided with longitudinally extending grooves35 Grooves 35 and 38 receive electrical conduits 31 and 38, which areconnected in any suitable manner to a source of electricaleenergy.

Conduit 31 preferably constitutes the live conduit and is provided withan annular contact portion 39 having a centrally disposed opening 4|therein. -In order to properly position contact 39 in bore 32, conduit31 is secured to an insulating sleeve 42 by means of arms 43 which passthrough suitable apertures 44 inthe wall of sleeve 42. Arms 43 are bentover so as to clamp sleeve 42 at 48. Sleeve 42 with conduit 31 securedthereto is lthen inserted into bore 32, preferably from the lower end,and forced upwardly through bore 32 until contact 39 is at the properWhile a frictional flt between sleeve 42 and bore 32 is usuallysuiilcient to retain the sleeve in proper position, suitable cement maybe used.

Contact 38 in groove 38 extends beyond the shoulder 31 and is then bentover to provide a Y portion 48, in engagement with shoulder 34, and aportion 49 in engagement with the wall of enlarged portion 33 of bore32. A metal ring 5| having internal threads 52 therein is positionedinenlarged portion 33 and clamps portions 48 and 49 of conduit 38 inplace. Metal ring 5| may be associated with body 3| in any suitablemanner. It is preferable that ring 5| t enlarged bore 33 snugly so as tobe retained by friction, but it may be cemented in place.

Ring 5|, in the illustrated embodiment, is adapted to receive anexternally threaded metal cap 53 having an internal bore 54 therein.Bore 54 freely receives base |8 of lamp I8, and. the Y. tapered walls 55thereof engage contact 24 and force lamp I8 into snug engagement withcontact 39. Cap 53 in addition completes the return circuit fromfilament I5, contact 24 to metal ring 5|, and conduit 38.

The bulb and socket structure just described is particularly useful inilluminating inscribed panels or dials, such as those used on radioreceiving and sending sets, and pressure and like dial and pointerinstruments. A typical installation is shown in Figure 5. In this gure arecess 3| is provided in the instrument body at one side of aninstrument 88, and said recess forms the socket already described. Thewall of instrument y 88 is provided with an aperture 82interconnectcateddirectlybelowsieevesothatlightrays from lamp I3 may bereilected from surface 84 through the body of prism 83 into instrumentcasing 8l. T assure proper projection of the light rays, the lower endof sleeve 42 may carry a bulls eye lens 88, which causes the normallydivergent rays of light from lamp I8 to pass out of lens 88 and strikesurface 84 as parallel rays.

The rays reflected by surface 84 pass through the body of prism 83 andinto the edge of a light transmitting panel or dial 88.

The rays entering dial 88 are diffused in suitable manner throughout thebody of the dial so as to illuminate the markings and numerals on thedial face. A preferred method-of diffusing the light and-illuminatingsuch a dial is illustrated in the copending application of MaximilianKlein and William E. Pfeifer entitled Illuminating indicating instrumenSerial No. 243,045, filed on even date herewith.

Although the preceding description contemplates that the body 3| be ofinsulating material, it will be appreciated that body 3| may be formedof metal provided conduit 31 is suitably insulated therefrom. If such astructure is resorted to, ring 5| and conduit 38 may be omitted and cap53 may be screwed directly into the metal body portion which can beconnected in a suitable manner to the ground lead of the electricalsource and serve to complete the electrical circuit.

A modified form of the present invention is illustrated'in Figures 5 to8, inclusive. In this form of the invention many of the parts areidentical to those previously described and will be given the samereference numerals and the detailed description thereof will be omitted.

Lamp Illa comprises a glass bulb I2 having the usual filament I3 thereinand protruding lament connections I4 and I5 extending from the rear ofthe glass bulb. Base assembly |8a comprises an insulating sleeve 2| andspring metal contacts |1a and 24a formed .from relatively narrow stripsof metal. Filament lead I4 is co'nnected by a suitable solderingoperation to contact |1a at I9 while contact 24a is similarly connectedat 28 to filament lead .|5. v

Glass bulb I2 with contacts Ila and 24a connected thereto is theninserted into sleeve 2| and the sleeve is filled with cement 21 bypouring the cement in its plastic condition into the open rear end ofbulb assembly Illa. 'I'he cement 21 completely fills the space betweenthe glass bulb I2 and sleeve 2| to connect these elements and contactstrips I1a and 24a into a unitary assembly. Y

While lamp Ilia may be used in any suitable socket structure, socketstructure Ila similar in all respects to socket II, except for the livecontact 31a comprises a relatively narrow strip of metal extendingupwardly through groove 35 and secured to sleeve 42 by means of arms 43in the manner heretofore described. The annular contact 39, however, isomitted and the upper end of contact strip 31a is bent over the end ofsleeve 42 to provide a contact element 81.

Lamp Ilia is inserted through the upper end of bore 32 and contactportion 88 at the end of contact I1 engages .contact 81 to complete thecircuit to bulb |841. Contact portion 89 at the end contact strip 24engages conduit 38 at a point slightly above sleeve 42 to complete thereturn circuit from lamp Illa.

Contact portions 88 and 89 are bowed outwardly vat 1| and are compressedas the bulb Illa is inl`tact indicated by numeral 31a, is preferred'.Con- 'serted into bore 32. These contact portion therefore, will ex.outwardly due to the spring material and bear upon the wall of groove35 and conduit 38, respectively, to retain lamp lila in bore 32.

The circuit in this form-of the invention is completed through lamp lilawithout passing through cap 53 and ring 5I. As a consequence, theseparts, although illustrated as being of metal, may be formed of anysuitable material, including insulating material, without aifecting theoperation of lamp lila and ring 5l may, if desired, be omitted.

Cap 53 in this form of the invention, through surfaces 55, serves topress bulb Illa closely upon contact 61 to assure a good contact at thispoint and prevent accidental injury to the bulb base which otherwisewould be exposed.

A further modied form of the invention is disclosed in Figure l0. Inthis form of the invention, the socket structure and bulb structure areidentical to that shown in Figures 1 through 4, except that the glassbulb portion is elongated to provide a glass bulb I2b having a filamentl3b therein. The bulls eye lens 65 is omitted and a prism 63h having avertical light transmitting face 15 in place of reflecting surface 64 isprovided. Face 15 coincides withthe vertical'wall of bore 32. As seen inFigure 10 the coiled portion of filament I3 is disposed directlyopposite face 15 and substantially centrally of bore 32. As aconsequence, lament i3 for all practical purposes constitutes` a pointof illumination, and the rays of light therefrom radiate in alldirections. Certain of these rays pass through face 15 and prism 63hinto the edge of the dial to effect illumination in the mannerheretofore pointed out.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured byV United States LettersPatent is:

1. A lamp and cap assembly, consisting in a cap having a cup-like body,a finger grip portion surrounding the closed end of said cup-like body,and a threaded portion for securing said assembly in a socket, a lamphaving a base freely tting in the open end of said cup-like body withthe bulb protruding therefrom, said lamp having a positive contactextending along beside said body beside a portion of said protrudingbulb beyond said body and the adjacent end of said base and 'a negativecontact for completing the circuit through said lamp.

2. The lamp and cap assembly defined in claim l wherein said negativecontact extends along a portion of said protruding bulb and beyond saidbody and the adjacent end of said base in spaced relation to saidpositive contact.

3. The lamp and cap assembly defined in claim 1, wherein said negativecontact extends beyond the other end of said base in position to begripped between the inner end wall of said cuplike body and said base.

4. A'n electric lamp consisting of a sealed bulb and a filament havingends projecting from the bulb, an insulating sleeve having a portionthereof telescoped on said bulb, a pair of contacts within said sleeveconnected to the ends of said filament, one' of said contacts having anexposed end protruding from and lapping one end of said sleeve and theother contact having an exposed end protruding from and lapping theother end of the sleeve, and cementitious material lling said sleevebeyond said portion providing a base having one contact at the back ofsaid sleeve and another contact forwardly of saidl sleeve.

5. An electric lamp, comprising a bulb having a filament, contact stripsdisposed at opposite sides of said bulb and connected to said illament.an insulating sleeve surrounding a portion of said bulb and said strips,one of said contact strips extending rearwardly beyond one end of saidsleeve and having its extending end bent over to form a contact at theexposed end of said base and the other contact strip projectingforwardly beyond the other end of said sleeve and having its extending,end bent over to form a contact between the ends of said bulb.

6. An electric lamp, comprising a bulb having' a filament, contactstrips disposed at opposite sides of said bulb and connected to saidfilament, an insulting sleeve surrounding a portion offsaid bulb andsaid strips, said contact strips projecting forwardly beyond the end ofsaid sleeve and having their extending ends reversely bent around theend of said sleeve to form spring contacts for frictionally retainingsaid lamp in assembled relation in a socket.

7. A lamp socket, consisting in a recess in a non-conducting housing ofan instrument or the like, an insulating sleeve disposed in said recessand having one end terminating a substantial distance inwardly from theface of said housing or the like, an electrical contact in the form of aring secured to said sleeve and overlapping said end of said sleeve, anda second electrical contact in the form of a ring embedded in saidhousing Y end of said sleeve.

9. The lamp socket dened in' claim '1, wherein said first contactcomprises a relatively narrow shoulder abutting said end of said sleeve.

10. An electric lamp, comprising a bulb having a lament, contact stripsat opposite sides of said bulb and connected to said filament, anopen-ended insulating sleevev surrounding said strips and telescopicallyreceiving approximately one half the length of said bulb, said sleeveprotruding beyond one end of said bulb to provide an open recess forreceiving a suitable cementitious material, and cementitious materialnlling said recess and the space between said bulb and sleeve to firmlyunite said bulb, said contact strips and said sleeve into a imitary lampassembly.

- KLEIN.

WILLIAM E. PFEFFER.

I+ CERTIFICATE OF CORRECTION. i A Patent No. 2,210,764.. August 6,1911.0.

MAXIMILIAN KLEIN, ET AL'. It is hereby 'certified that error alppearsinthe printed specification ofthe above numbered patent requiringcorrection as follows: Page 5, first column, lines 5? and 58, claim1,strike out the words "beside said body 'beside; and second column,line 29,clim 6, for "insulting" read --insulating; and that -the saidLetters PatentV should nel read with this correction therein that thesame may conform tothe record of the case inthe Patent office. A Y

signed and sealed this 10th day of september, AA. D. 191m.

Leslie Frazer, (Seal) Acting Commissioner of Patents.

